A former City of Flint employee is expected to plead to a misdemeanor Tuesday in the Flint drinking water case and agree to cooperate with prosecutors, the Free Press has learned.

Daugherty (Duffy) Johnson, 49, of Flushing, the former city utilities director, will become the third defendant to agree to a plea deal since Attorney General Bill Schuette launched his criminal investigation into the lead contamination of Flint's drinking water and deadly outbreaks of Legionnaires' disease in the Flint area that some experts link to the contaminated water, according to two sources familiar with the investigation.

Johnson is expected to plead no contest -- which has the same legal effect as a guilty pleas -- to a misdemeanor, in Flint district court.

Johnson was charged last December with conspiracy and false pretenses. Both are 20-year felonies.

Schuette has brought criminal charges against 15 current or former state or city employees in connection with the Flint public health crisis.Another city employee, Mike Glasgow, 42, of Flint, entered a conditional no contest plea to a misdemeanor in May 2016 and agreed to cooperate. All charges against him were later dismissed, before his plea was accepted.

A former employee of the state Department of Health and Human Services, Corinne Miller, 66, of DeWitt, pleaded no contest to a misdemeanor in September 2016. She has since testified at a preliminary hearing for Health and Human Services Director Nick Lyon, who is charged with involuntary manslaughter.

A spokeswoman for Schuette did not respond to an e-mailed message.Edwar Zeineh, a Lansing attorney representing Johnson, declined comment.

Flint's drinking water became contaminated with lead following a switch to the Flint River for its supply in April 2014, while the city was under the control of a state-appointed emergency manager.

Despite almost immediate complaints about the color, odor and taste of the water, the state did not acknowledge a lead contamination problem until about Oct. 1, 2015, long after tests showed elevated lead levels in tap water samples and other tests showed a spike in toxic lead levels in the blood of Flint children.